1. Field of the Invention
The present invention relates to a transflective display panel, and more particularly, to a display panel having an electroluminescent display panel and a transflective liquid crystal display panel.
2. Description of the Prior Art
Recently, electroluminescent (EL) display panels, such as organic electroluminescent display panels, have become popular flat displays, because of having the advantages of self-luminescence, wide viewing angle, fast response time, high illumination efficiency, low operating voltage, thin panel thickness, flexibility and a simple fabricating process. These EL display panels have been widely applied to all kinds of flat display products.
Please refer to FIG. 1, which is a cross-sectional schematic diagram illustrating an EL display panel according to the prior art. As shown in FIG. 1, the EL display panel 10 includes a TFT (thin-film transistor) substrate 12, an anode 14, an organic light-emitting layer 16, a cathode 18 and a transparent substrate 20. The TFT substrate 12 includes a substrate 22, a TFT 24 disposed on the substrate 22, and a passivation layer 26 covering the TFT 24 and the substrate 22. The anode 14 covers the passivation layer 26, and is electrically connected to a drain of the TFT 24 through a contact hole 28. In addition, the organic light-emitting layer 16 is disposed on the anode 14, and the cathode 18 is disposed on the organic light-emitting layer 16. The transparent substrate 20 covers the cathode 18.
The brightness of the EL display panel of the prior art is determined by the luminance of the organic light-emitting layer. When the brightness of the ambient light is larger, the ratio of the brightness of the organic light-emitting layer to that of the ambient light is reduced, so that the contrast ratio of the image displayed by the EL display panel of the prior art is reduced. In a worst case, the image displayed by the EL display panel of the prior art cannot be shown. In the organic EL display panel of the prior art, increasing the reduced contrast ratio should raise the luminance of the organic light-emitting layer so as to prevent the image displayed by the EL display from being affected by the ambient light with over-high brightness. However, raising the luminance of the organic light-emitting layer not only consumes more power, but also shortens the lifetime of the organic light-emitting layer. Therefore, to increase the contrast ratio of the EL display panel is an important subject when the brightness of the ambient light is too high.